In less than a month, hurricane season will begin, and all eyes will turn to the Atlantic. As with all meteorological forecasts, it is impossible to predict exactly how many storms will form, how strong they will be, and where they will travel, it is not too difficult to make a decent estimation of the severity of the season.
Last year, I did a decent job at my forecast in terms of numbers, but really did well with the location of these storms. I’m hoping to go 2 for 2 with my forecast for this year. My success last year was based on more of a data analysis, and using some math, to figure out similar (analog) years. Using those years, I was able to determine a common theme, which led me to my forecast.
This year, I’m doing something very similar except directing the focus of my forecast on key variables such as ENSO (el Nino Southern Oscillation) and the sea surface temperatures of the Atlantic. The results are probably some of the most interesting I’ve come across in a while.
Sea Surface Temperatures for the past 28 months have been above normal. This would generally indicate the likelihood of a higher than average hurricane season. I was able to go back through the past 32 years and find years of similar values and trends of these ocean water temperatures. Years of similar ocean temperatures were 1995, 1996, 1997, 2000, 2001, and 2003.
The same strategy was applied to the El Nino index. A moderate to strong La Nina we have seen over the past winter has been weakening over the course of the past 4 months. It has weakened towards neutral, and all forecasts appear to take it positive and into a weak or moderate phase, which would indicate a wearier than normal hurricane season (more on this in just a second…). The similar years found for the ENSO are 1985, 1996, 2001, 2006, 2009.
Using these data points and information, I combined the values, and came up with four years within the past 32 with similar values: 1996, 2001, 2006, 2009. These four years had 14, 15, 10, and 9 storms, respectively. Just looking at these stats, you are looking at an above average tropical storm season.
Going back to the years with similar ENSO values, I stated forecasts indicate it will turn positive and become an El Nino. Previous analog years show differently. Below is a graph of all ENSO values with similar values. You can see 5 out of the 7 stay just below neutral. This is why I feel the forecasts are just a bit off. This would favor a more active hurricane season.
If you look at analog years of the sea surface temperatures, it would seem to indicate the same story. Water temperatures which are already warm should continue to become warmer than usual. You can see by June, July, and August, temperatures should be between 0.1 and 0.2 degrees celsius above normal. While it doesn’t seem like much, this is a huge factor in hurricane development.
Using all this information and tying it all up, here is my forecast for this year. I see 14 named storms, which is 4-5 above normal, 7 of them becoming hurricanes, 3 of them becoming major hurricane status.
The next logical question is to ask where these storms will go. Looking at sea surface temperature patterns and these analog years, I expect most of these storms to stay away from the United States. The main concern would be for the island of Bermuda, as a number of storms could impact that area. The Yucatan could be hit hard as many storms traveling across the Caribbean would stay suppressed. As far as numbers, look for 6 of the 14 storms to make landfall somewhere in North America, 3 of those 6 striking the United States. In particular, the main threat seems to be a track taking storms over Florida, redeveloping off the coast of Georgia, and up near Cape Hatteras, North Carolina. Of course, all areas should be prepared for the possibility of a tropical system striking land, but these are the areas I feel have the highest threat.
